1. Field of the Invention
The present invention relates to a two step process for forming a polymeric coating on a porous substrate. In the present invention the porous substrate moves from a first bath which applies a first monomer to the porous substrate to a second bath which has a common interphase with the first bath. A second monomer is applied to the substrate in the second bath and the two monomers condensed to form a polymer layer which is effective as a reverse osmosis membrane.
2. Prior Art
U.S. Pat. No. 4,277,344 discloses interfacially synthesized reverse osmosis membranes wherein an aromatic polyamide is derived from a monomeric aromatic polyacylhalide which is three fold or higher in acyl functionality and a monomeric arylene polyamine.